By Kim Yoo-chulU.S. President Donald Trump's recent decision to delay Secretary of State Mike Pompeo's trip to North Korea has raised concerns that nuclear negotiations may face a deadlock, derailing the months of tepid progress between Washington and Pyongyang.Cheong Wa Dae said it regrets the delay, but spokesman Kim Eui-kyeom said President Moon Jae-in will still meet North Korean leader Kim Jong-un in Pyongyang next month as planned.The upcoming inter-Korean summit will cover specific details on the North's denuclearization, which have been touched on but seen little progress. Political analysts in Seoul say Moon will try to get concessions from Kim regarding "concrete actions.""Washington needs to see a specific action plan from Pyongyang toward nuclear disarmament as this is believed to be key to the denuclearization of the Korean Peninsula. President Moon will try to persuade Kim to hand over a list of his nuclear weapons, ICBMs and unknown test sites at the upcoming talks," said Kim Joon-hyung, a North Korean expert at Handong University, Monday. The North is said to have rejected Pompeo's requests to hand over 60 percent to 70 percent of its nuclear warheads within six to eight months. Prof. Kim said the North wants to see a gradual progress of denuclearization based on the level of security guarantees from the United States, as a "nuclear list" is its "only leverage.""The North was hoping to report its nuclear weapons programs, which are now in operation, to the United States in exchange for security guarantees. It also wants the lifting of economic sanctions for additional disclosures. President Moon is expected to ask the North to continue negotiations and tell him of the estimated benefits his regime can get," the professor said.The Singapore summit June 12 between the United States and North Korea didn't arrive at a nuclear deal because there was no agreement that would encourage Pyongyang to act "something differently," he added.Analysts say negotiating with North Korea is going to be a long and twisted process as indicated by previous talks. These showed that the reclusive country wanted to hold onto its nuclear devices for as long as possible while obtaining as many concessions as possible."My understanding is that North Korea doesn't want to walk away from the negotiations. President Trump said the delay of Pompeo's visit to Pyongyang was because of deepening trade friction with China, which I can't agree with as Trump wants an exit strategy just in case," said Lim Eul-chul of Kyungnam University's Graduate School of North Korean Studies."North Korea wants some cards in their hand and to have some degree of leverage. This is what President Moon should bear in mind at the upcoming summit with Kim Jong-un. If conditions are met, then the nuclear talks will proceed further," the expert said. It's unclear what will happen next. But Trump could reverse course as he's done before. In May, he suddenly canceled his summit with Kim Jong-un planned for two weeks later, claiming a meeting was "inappropriate" at that time. Then on June 1, he decided to meet Kim after all.